The following 9 drugs have been associated with the highest levels of addictiveness:

Xanax – a benzodiazepine (class of psychoactive drugs) with fast-acting sedating and relaxing effects. Designed for serious panic disorders and anxiety.

Valium – a benzodiazepine, which is very habit-forming and produces ‘highs’ that resemble drunkenness.

Klonopin – similar to Valium and Xanax.

Oxycodone – an opiate, known under brand names Oxycontin and Percocet. It changes the way the brain responds and has been compared to heroin. It produces a euphoric and sedative effect.

Codeine – an opiate that is prescribed for coughs and pain and can often be found in prescription-strength cough syrups.

It’s often combined with other medications and has been popularized as ‘purple drank’ – a concoction made with soda and candy.

Amphetamines (Speed) – stimulants, sold under different brand names, for example, Adderall. They are often abused for their energizing effects by people who want to (or need to) skip on sleep.

Ritalin – a stimulant that increases levels of dopamine in the brain. Readily available and generously prescribed for ADHD.

Demerol – an opioid pain reliever that has violent withdrawal symptoms. Darvocet – a commonly abused pain killer. It has been taken off the market in the US in 2010 due to heart complications it can cause. - Online Sources